Be flirty to every girl you meet, especially around them, and including them. Always make sure there is sexual tension.
It will get past the friendzone barrier because you are just a flirty guy in general. date other girls though. Important. Don't waste your time if you have an exclusive gf though.
Make sure there is light playful keno. Don't get to heavy yet. Slap her ass, cop a feel, tease her. The fun stuff. Not the intimate stuff.
All the above is set up. Then, at a time when you are both single, start hanging out 1on1 alot. Step up the kino more, and also kinda pull back from making moves on other girls. But keep it light. Do some fun early date type things (not movies/dinner). And then make a move.
I have had success with this several times. The first part takes a little time, and needs to go slow. Pick up the pace with the second part though. I'll be honest, it has always ended in a LTR. Good ones too. But the window to change the tone of the relationship is small. When you go from the first phase to the second, you got to keep the pace quick, so she doesn't really think about it too much and act before she gets used to you as a friend again.
***As a side note, if they are friends and you aren't interested in them, why game them? Good way to lose a friend IMO. Not lecturing though